Function compute_predecessors

crates/codegen/src/ir.rs:2694–2721

(blocks: &[Block])

}

fn compute_predecessors(blocks: &[Block]) -> Vec<u32> {
    let mut predecessors = vec![0u32; blocks.len()];
    if blocks.is_empty() {
        return predecessors;
    }

    predecessors[0] = 1;
    let mut current = BlockIdx(0);
    while current != BlockIdx::NULL {
        let block = &blocks[current.idx()];
        if block_has_fallthrough(block) {
            let next = next_nonempty_block(blocks, block.next);
            if next != BlockIdx::NULL {
                predecessors[next.idx()] += 1;
            }
        }
        for ins in &block.instructions {
            if ins.target != BlockIdx::NULL {
                let target = next_nonempty_block(blocks, ins.target);
                if target != BlockIdx::NULL {
                    predecessors[target.idx()] += 1;
                }
            }
        }
        current = block.next;
    }
    predecessors
}

fn duplicate_exits_without_lineno(blocks: &mut Vec<Block>, predecessors: &mut Vec<u32>) {
    let mut current = BlockIdx(0);